EPS8 and holoprosencephaly: The defects caused by Eps8 are dose dependent; low doses (50 pg) of Eps8 result in cyclopia and a shortened A-P axis, moderate doses (200 pg) show varying degrees of cyclopia, microcephaly, and shortening and arching of the A-P axis, and high doses (1 ng) result in varying degrees of anencephaly, shortening and arching of the A-P axis, and spina bifida.